fix: remove CMAKE_PREFIX_PATH from Qt build to hide OpenSSL

The -no-openssl and empty OPENSSL_DIR vars didn't prevent Qt from finding
the vcpkg OpenSSL library because CMAKE_PREFIX_PATH included the entire
vcpkg installed folder.

Remove CMAKE_PREFIX_PATH entirely during Qt configure. The -system-zlib flag
will find zlib through the vcpkg toolchain, and Qt won't have any path to find
OpenSSL at all.

This ensures ONLY libtorrent links OpenSSL, eliminating duplicate symbols.

Author: vectorrilke

.github/workflows/ci_windows_arm64_native.yaml

@@ -131,10 +131,6 @@ jobs:
             -prefix "${{ env.qt_target_root }}" `
             -qt-host-path "C:/Qt/${{ env.qt_version }}/msvc2022_64" `
             -system-zlib -schannel -no-openssl -qt-sqlite -sql-sqlite -no-sql-mysql -no-sql-odbc -no-sql-psql -c++std c++20 -- `
-            -DCMAKE_PREFIX_PATH="$vcpkgRoot/installed/${{ env.vcpkg_triplet }}" `
-            -DOPENSSL_DIR="" `
-            -DOPENSSL_CRYPTO_LIBRARY="" `
-            -DOPENSSL_SSL_LIBRARY="" `
             -DCMAKE_TOOLCHAIN_FILE="$vcpkgRoot/scripts/buildsystems/vcpkg.cmake" `
             -DVCPKG_TARGET_TRIPLET=${{ env.vcpkg_triplet }}